Loctite Sealing Compound (250ml) - 223856 is a permanent, flexible sealant designed to provide an instant, waterproof seal for a wide range of surfaces. It is resistant to water, oil, and most chemicals, and is ideal for sealing porous and non-porous surfaces, filling gaps, and bonding dissimilar materials. It cures to a strong, resilient bond that won't shrink, crack, or harden over time.